Title Substation Auxiliary Transformer from Rectifier Transformer Secondary. Reference Number PDS 01 (RIC Standard: EP SP)

Transcription

1 Discipline Engineering Standard NSW Category Electrical Title Substation Auxiliary Transformer from Rectifier Transformer Secondary Reference Number PDS 01 (RIC Standard: EP SP) Document Control Status Date Prepared Reviewed Endorsed Approved Mar 05 Standards and Systems Refer to Reference Number Signalling Standards Engineer T Moore GM Infrastructure Strategy & Performance M Owens Safety Committee Refer to minutes of meeting 24/01/05

2 Disclaimer Australian Rail Track Corporation has used its best endeavors to ensure that the content, layout and text of this document is accurate, complete and suitable for its stated purpose. It makes no warranties, express or implied, that compliance with the contents of this document shall be sufficient to ensure safe systems of work or operation. Australian Rail Track Corporation will not be liable to pay compensation in respect of the content or subsequent use of this document for any other purpose than its stated purpose or for any purpose other than that for which it was prepared except where it can be shown to have acted in bad faith or there has been willful default. Document Approval The technical content of this document has been approved by the relevant ARTC engineering authority and has also been endorsed by the ARTC Safety Committee. Document Supply and Control The Primary Version of this document is the electronic version that is available and accessible on the Australian Rail Track Corporation Internet and Intranet website. It is the document user s sole responsibility to ensure that copies are checked for curency against the Primary Version prior to its use. Copyright The information in this document is Copyright protected. Apart from the reproduction without alteration of this document for personal use, non-profit purposes or for any fair dealing as permitted under the Copyright Act 1968, no part of this document may be reproduced, altered, stored or transmitted by any person without the prior written consent of ARTC. March 2005 Page 2 of 14

3 About This Standard This document details the whole of life performance requirements for the purchase and maintenance of a substation indoor auxiliary transformer that is supplied from one of the 600 V secondary windings of a rectifier transformer. The substation auxiliary transformer provides the supply for the auxiliary services in Australian Rail Track Corporation (ARTC) traction substations. This document does not cover auxiliary transformers supplied from a rectifier transformer with 2420 V secondary windings or auxiliary transformers that are supplied from a high voltage busbar. Auxiliary transformers with a three-phase 220 V secondary winding are also not covered. March 2005 Page 3 of 14

4 Document History Primary Source RIC Standard EP SP Version 1.0 List of Amendments ISSUE DATE CLAUSE DESCRIPTION /01/2005 Reformatted to ARTC Standard /03/2005 Disclaimer Minor editorial change March 2005 Page 4 of 14

5 Contents About This Standard...3 Document History Scope and Application References Australian Standards ARTC documents Drawings Definitions and abbreviations Introduction Functional characteristics General Whole-of-life cost Performance characteristics Technical characteristics Rated insulation level Harmonic voltages Rating plate Terminal arrangement Enclosure Earth terminal Lifting attachments Temperature-rise limits Finish Maintenance...12 March 2005 Page 5 of 14

6 9. Tests Acceptance tests Periodic tests Data set associated with the equipment Equipment manuals Test results Life cycle costing Technical information Technical schedule...14 March 2005 Page 6 of 14

7 1 Scope and Application This document details the whole of life performance requirements for the purchase and maintenance of a substation indoor auxiliary transformer that is supplied from one of the 600 V secondary windings of a rectifier transformer. The substation auxiliary transformer provides the supply for the auxiliary services in Australian Rail Track Corporation (ARTC) traction substations. This document does not cover auxiliary transformers supplied from a rectifier transformer with 2420 V secondary windings or auxiliary transformers that are supplied from a high voltage busbar. Auxiliary transformers with a three-phase 220 V secondary winding are also not covered. The requirements of this document apply from this document s date-of-issue to all new auxiliary transformers that are supplied from one of the 600 V secondary windings of a rectifier transformer. 2 References 2.1 Australian Standards The following Australian Standards are either referenced in this document or can provide further information. AS Degrees of protection provided by enclosures for electrical equipment (IP Code) AS Power transformers Part 1: General AS Power transformers Part 2: Temperature rise AS Power transformers Part 3.0: Insulation levels and dielectric tests General requirements AS Power transformers Part 3.1: Insulation levels and dielectric tests External clearances in air AS Power transformers Part 5: Ability to withstand shortcircuit AS Power transformers Part 6: Determination of transformer and reactor sound levels AS Colour standards for general purposes AS Dry-type power transformers AS/NZS Electromagnetic Compatibility (EMC) Part 3.6: Limits Assessment of emission limits for distorting loads in MV and HV power systems (IEC :1996, MOD) 2.2 ARTC documents PDS 16 Transformer Loss Evaluation. March 2005 Page 7 of 14

8 PDS 04 System Substation Earthing. 2.3 Drawings The following drawings form part of this document: None. 3 Definitions and abbreviations For the purpose of this document the definitions given in AS 2374 apply. In addition the following definitions also apply: Primary winding The winding that receives the active power from the supply system, usually the winding having the highest rated voltage. Principal tapping Is the mean tapping position. It is also the tapping to which the rated quantities are related. Secondary winding The winding that delivers the active power to the load circuit, usually the winding having the lowest rated voltage. 4 Introduction The 1500 V traction system is unearthed, therefore the secondary of the rectifier transformer and the primary of the auxiliary transformer cannot be earthed. Special design considerations are required to ensure that the transformer will not be affected by faults on the traction system. 5 Functional characteristics 5.1 General The substation auxiliary transformer provides the supply for the auxiliary services in ARTC traction substations. The transformer primary winding is supplied from one of the secondary windings of a rectifier transformer. The rectifier transformer supplies a series bridge rectifier for the 1500 V traction system. The auxiliary services include lighting, low voltage power, dc power supplies, ventilation and compressed air. They are not used for supplying dc traction loads. The auxiliary services may be three-phase 415 V or single phase 240 V. The traction substations are in the area bounded by Newcastle (north), Dapto (south) and Lithgow (west). 5.2 Whole-of-life cost The selection of the most suitable transformer shall be made on the basis of minimising the whole-of-life cost. The following factors must be considered in determining this: March 2005 Page 8 of 14

9 Initial purchase price. Cost of changes to the Technical Maintenance Plan and Service Schedules or the creation of new manuals and schedules. Cost of manuals. Cost of maintenance. Cost of replacement parts. Cost of inventory spares. Environmental costs. Electrical losses. Refer to document PDS 16 Transformer Loss Evaluation for the method of evaluating transformer losses. Cost of installation. Reliability and cost of failures. Cost of modifications to other parts of the installation. Lifetime of equipment. Discount rate. Cost of staff training. Cost of decommissioning and disposal. Cost of special tools. Cost of changes and management of drawings. 6 Performance characteristics Number of phases 1 or 3. Frequency Type Type of cooling 50 Hz. Indoor, Enclosed dry-type. Air natural. Rated Voltages Primary 600 Vrms Secondary 240 Vrms (1) or 415 Vrms (3) Tappings Full kva tappings on the primary winding at ± 2.5% and ± 5% of the principal tapping. The tappings shall be controlled by off-circuit bolted links. March 2005 Page 9 of 14

10 System highest voltage Primary 3.6 kvrms Secondary 1.1 kvrms System earthing Non-effectively earthed. Rated insulation level Primary 16 kvrms (power frequency) Connection vector symbol Neutral terminal Dyn 1 (three-phase transformer). Star point of lower voltage winding shall be connected to a suitable terminal and fully insulated from earth. Impedance voltage at rated Refer to AS , Table 1. current and 75 C Sound pressure level Refer to AS , Appendix AA. Special physical characteristics Refer to section 7. 7 Technical characteristics 7.1 Rated insulation level The primary winding(s) are connected to the unearthed secondary of the rectifier transformer. During fault conditions, the voltage to earth of this winding can exceed 3.5 kvdc. Special attention is drawn to the rated insulation level requirements in section Harmonic voltages The rectifiers create high harmonic distortion of the current waveform. This distorted current waveform interacts with the impedance of the rectifier transformer resulting in harmonic voltages. The design of the auxiliary transformer must therefore take these harmonic currents and voltages into account. 7.3 Rating plate The rating plate shall meet the requirements of AS , Clause 7, and shall include a diagram of connections. A terminal marking plate complying with the requirements of AS , Clause ZC7, shall also be attached to the transformer. The plates shall not be attached to a removable cover. 7.4 Terminal arrangement The three primary winding leads and the four secondary winding leads (two leads per winding for 240 V) shall be brought out from each transformer winding and terminated on screwed terminal studs suitable for use with crimp lugs. The terminals shall be suitably proportioned and marked to the requirements of AS , Clause ZC4. An insulated barrier shall separate the primary terminals and the secondary terminals. The complete arrangement shall be enclosed in the transformer enclosure. March 2005 Page 10 of 14

11 7.5 Enclosure The transformer shall be enclosed to meet the requirements of AS 2735 Clause and AS 1939 with a degree of protection of IP21. A method for securing the input and output cables shall be incorporated into the enclosure. 7.6 Earth terminal An earthing terminal suitable for the connection of a 70 mm 2 cable shall be located externally on the transformer enclosure. 7.7 Lifting attachments Suitable lifting lugs shall be provided for lifting the transformer. 7.8 Temperature-rise limits The transformer shall be capable of continuous operation at rated power without exceeding the maximum temperature-rise limits as specified in AS , Clause Finish The transformer enclosure (internal and external) shall be painted with a smooth semi-gloss enamel. 8 Maintenance The relevant ARTC Technical Maintenance Plans (TMP) shall be adhered to for the maintenance of the type of transformer. Where a new type of transformer is purchased and installed that is not covered by the TMP, then a new service schedule shall be created and the TMP updated. This shall include: The Maintenance Policy, defining the practical means of maintaining the equipment. The tasks to be performed at each level of maintenance and staff skill levels required. Test equipment and tools. It is preferable that the period for routine maintenance shall not be more frequent than for the types of transformers currently detailed in the ARTC Technical Maintenance Plan. 9 Tests 9.1 Acceptance tests Routine tests shall be carried out on each transformer to AS Clause The results shall be recorded. A record of a test certificate for type tests carried out on a similar transformer to AS Clause shall also be available for each transformer. March 2005 Page 11 of 14

12 9.2 Periodic tests Refer to ARTC Technical Maintenance Plan. 10 Data set associated with the equipment The following data shall be maintained for each transformer. This data shall be the property of ARTC and maintained by the Maintenance Provider responsible for the installation in which the transformer is installed Equipment manuals The Equipment Manuals must be provided for the installation and shall include full instructions for the preventative, surveillance and corrective maintenance, comprehensive fault diagnosis, rectification procedures and staff training requirements. It shall include all drawings needed for the above. All drawings shall show sufficient detail to enable satisfactory maintenance of the equipment Test results The results of all tests relating to the transformer, including acceptance tests and periodic and corrective maintenance tests, shall be recorded Life cycle costing All the data and assumptions pertaining to the determination of the whole-of-life cost calculations shall be recorded Technical information The information listed in the attached Technical Schedule shall be maintained for each transformer. March 2005 Page 12 of 14

13 11 Technical schedule Manufacturer... Serial number... Year of manufacture... Rated primary voltage... V Rated secondary voltage... V Rated power... kva Connection vector symbol... Maximum temperature rise of windings... C Impedance voltage at rated current and 75 C/115 C* (Expressed as percentage of rated voltage)... % No-load current with rated voltage applied to the principal tapping (Expressed as percentage of rated current)... % No-load current with 110% of rated voltage applied to the principal tapping (Expressed as percentage of rated current)... % No-load loss... W Load loss... W Type of core steel - hot or cold rolled... Brand or trade name and grade of core steel... Flux density based on net cross-section of steel with rated voltage at rated frequency applied to the principal tapping Limbs... T Yoke... T Mass of windings only... kg Mass of transformer core and windings only... kg Mass of one transformer complete with metal enclosure... kg Mean audible sound level... db March 2005 Page 13 of 14

14 Voltage withstand test: primary terminals - Lightning impulse withstand voltage... kv p - Power frequency withstand voltage... kv rms secondary terminals - Power frequency withstand voltage... kv rms Terminals, minimum clearance in air: primary secondary mm mm between phases... mm phase to earth... mm Is heat-shrink material provided on the primary terminals?... * YES / NO Type of insulating material used for windings... Type of material used for windings - copper or aluminium... Temperature class of insulation... Overall transformer dimensions: Length... Width... Height... mm mm mm Protective treatment applied to: Internal surfaces... External surfaces... * Cross out where not applicable. Departures from Specification Are there any departures from the requirements of this Specification... * YES / NO Departures from the requirements of this Specification must be highlighted. March 2005 Page 14 of 14